The present invention relates to a high-voltage electric field generating system and a fryer equipped with the system, wherein a high-voltage electric field is generated in a container to prevent deterioration of oil.
In general, fried-food factories utilize fryers that are fixed at a place. This type of fryer is equipped with a large oil container that can hold and heat cooking oil. Since a large amount of cooking oil deteriorates daily, required is frequent replenishment of oil, which consumes enormous amount of time and labor. Furthermore, certain types of cooking oil are very expensive, causing a cost disadvantage compounded by the needed frequent replenishment. Therefore, it is desirable to have a system that can slow down deterioration of cooking oil.
Kokai Patent Journal No. HEI 11[1999]-113761 disclosed an example of frying device capable of slowing down deterioration of cooking oil. In the disclosed frying device, a plate member with many holes is installed at the bottom of an oil container, and the plate member is used as an electrode for generating a high-voltage electric field. With this type of electrode, electromagnetic fields concentrate around the rims of the aforementioned holes, thus generating a high-voltage electric field. However, a problem is that it is difficult to generate a desired level of high-density electromagnetic fields with the above structure, since the total area of the acute-angle portions is small compared to the entire surface area of the electrode. As a measure to solve this problem, we could increase the plate area of the electrode disclosed in the aforementioned Kokai Patent Journal No. HEI 11[1999]-113761, and make more holes to increase the acute angle portions for generating a desired level of high-density electromagnetic fields. However, with this type of structure, the aforementioned electrode will occupy most of the oil container so that productivity will decrease. To maintain productivity, the fryer must be made large.
The present invention was made in consideration of the situation surrounding the prior art as described above. It is an object of this invention to provide a high-voltage electric field generating system and a fryer therewith in a compact structure, wherein the capacity of an oil container is not taken up too much; a high-voltage electric field is generated efficiently; and fast deterioration of cooking oil can be prevented.
According to the first aspect of this invention, there is provided a fryer, having an oil container to hold oil for frying food; an electrode, having tip portions, installed in the aforementioned oil container; and a high-voltage power supply which is connected to the aforementioned electrode to generate a high-voltage electric field in the oil by creating dense electromagnetic fields around the tip portions. It is preferable that the aforementioned electrode has a plurality of tip portions that are formed adjacent to one another with a predetermined clearance in between. More preferably, the aforementioned electrode is in a shape of a screw rod having one end portion and the other end portion; and the aforementioned tip portions are a screw thread continuously provided with a predetermined pitch.
According to the electrode structure above, it is possible to obtain dense electromagnetic fields around the tip portions in spite of the small area occupied by the electrode. This is due to many pointed tip portions formed on the electrode. Thus, a high-voltage electric field can be generated in the oil, and deterioration of the oil can be effectively prevented.
According to one embodiment of the present invention, the aforementioned high-voltage power supply is connected to one end portion or the other end portion of the electrode which is in a form of a screw rod. When there are a plurality of oil containers, it is preferable that the aforementioned electrode is provided in each oil container; and the electrode in each oil container is connected in series to one end or the other end of the electrode in another oil container. It is preferable also that the aforementioned high-voltage power supply is connected to either one end or the other end of the electrodes connected in series.
According to the configuration above, it will be easy to provide an electrode in each oil container, even in case of a fryer comprising a plurality of oil containers of equal size or various sizes. Also, because it is not necessary to provide a high-voltage power supply for each electrode, the entire construction of the system can be made compact.
According to another one embodiment of the present invention, it is preferable that the aforementioned electrode has an attachment member for installing the electrode to the aforementioned oil container in a manner that it can be easily attached or detached. According to this configuration, since no fastening members such as screws are used, dust such as metal particles are not generated in the oil container. In addition, the electrode may be removed for cleaning or for other purposes, even while the container is full of oil.
Furthermore, in case a food holding member for holding food is provided in the oil container, it is preferable that the aforementioned electrode is installed between the aforementioned food holding member and an inner face of the oil container.
Furthermore, the system may include a holding unit that holds the aforementioned electrode close to, but at a predetermined distance away from, an inner face of the aforementioned oil container. The aforementioned distance should be set to a distance at which no discharge would occur between the tip portions of the aforementioned electrode and the inner face of the oil container.
According to the configuration above, the electrode can be installed on the sidewall of the oil container without having to make the fryer large. In this case, it is possible to prevent discharge since the electrode can be installed at a certain distance away from the inner face of the oil container.
According to the second aspect of the present invention, there is provided a system comprising: an electrode having tip portions, installed in a container that partitions off a space where food is stored or processed; and a high-voltage power supply connected to the aforementioned electrode. When voltage is applied to the electrode by the high-voltage power supply, electromagnetic fields concentrate around the tip portions and a high-voltage electric field is generated in the aforementioned space of the container.
The above configuration provides a high-voltage electric field generating system, which can be used for a device such as a fryer having a container or a space for storing or processing food.
Other features and remarkable effects of the present invention can be more clearly understood by referring to the following specific embodiments and the attached drawings.